Mg-based alloys are prospective materials for reversible hydrogen storage in the form of metallic hydrides. Usually, hydrogen saturation is carried out at high temperatures and high hydrogen pressures. This is the reason for the high cost of metallic hydrides in comparison with other hydrogen storage methods. Electrochemical hydriding, on the other hand, can be realized at room temperature. Moreover, this process does not need any hydrogen atmosphere. In the presented work, electrochemical hydriding of several Mg-Ni-Mm-based alloys (Mm = mishmetal) is performed. Hydriding efficiency, mechanism and kinetics are described. It is shown that the additions of Ni, Mm and the formation of eutectic structures support hydriding of alloys.